Tanning agent



Patented Dec. 5, 1933 UNITED STATES PATENT oF F1ca.

7 1,938,022 TANNING AGENT Johann Huismann,

Leverkusen-on-the-Rhine,

and Gustav Mauthe, Cologne-Holweide, Germany, assignors to I. G. Farbenindustrie Aktiengesellschaft, Frankfortfonthe- Main, Germany 7 No Drawing. Application February 7, 1931, Serial N0. 514,306, and in Germany February 27, 1930 2 Claims. (Cl. 260 -129) The present invention relates to new tanning agents. According to this invention the materials to be tanned in accordance with 'tann'ers practice are treated with a water soluble com- I:-IH some 1 o I, r 7 o so,

stituted or unsubstituted bior polynuclear a'rylsulfone-arylamide derivatives of the benzene or naphthalene series with chain-like linkage in am but v liltliout limiting it thereto? which the sulfone imide groups combining the aryl nuclei may be partly replaced by aliphatic or aromatic carboxylic acid amide groups, at least one of the nuclei containing a sulfonic acid group; These new tanning agents, are generally colorless powders being easily soluble in water. They are obtainable'according to methods described in the British Letters Patent No. 333,559, Examples to' '7.

The following examples illustrate the inven- Ezcammle 1 Drenched, unhaire d goats skins (free from' lime) are treated'with of almost completely neutralized but"stillacetic acid reacting bis- (1:2-dichlorobenzene 4 sulfonyl -3-aminobenzene-l-sulfonyl) benzidine m m disulfonic acid with the addition of 3.3% of lactic acid in 300% of water until completely tanned. (All the figures given refer'to the weight of the unhaired skins.)

The tanning agent is obtainable by condensing bis-(3e amino benzene sulfonyl) benzidine-mm'-disulfonic acid (compare British Letters Patent No. 333,559, Example 6) With1.2-dichlorobenzene-4 -sulio'chloride analogously to the process as described in Example 5 of the said Letters Patent and corresponds to the formula:

SOaNa According to the thickness of the skins. the tanning requires three to five days. After tanning the skins are well rinsed and oiled from the grain. 'The finished curried leather is soft,

plumpjandlorig fibered and shows great similarity to leather tanned with vegetable tanning agents. It dif fers, however, advantageously from the latter in its pure White color and practically complete fast'ness to light.

Example 2 Unhaired-skins pickled with apickle consisting of :-1% of commercial formic acid, 8% of sodium chloride; 1 00% of water are tanned'ina fulling vessel with 15% strength of partly neutralized bis (1 Z-dichlorobenzene-4-sulfonyl-3- aminobenzene-l -sulfonyl) diamino -stilbene-disulfonic acid of the formula:

This re-tanning confers upon the leather a re markable fullness. The color of the leather is lighter than that obtained by the often practiced sumach re-tanning. 8-0

SOaNa I I $11 SOBNE IIIH V v S02 S03 c1 1 having a weakly acid reactionto Congo red in 100% bath without further addition. The Example 4 bis (1.2 dichlorobenzene-4-sulfonyl-3-aminobenzene-1 -sulfonyl) -diaminostilbene-disulfonic acid may be produced analogously to the process described in Example 1 of British Letters Patent No. 333,559, by causing one molecular proportion of 4.4-diamino-stilbene-disulfonic acid to react with two molecular proportions of 3-nitro-benzene-sulfochloride, reduction of the resulting condensation product and condensation of the di- ITTH 2 amino compound with two molecular proportions of 1.2-dichlorobenzenel-sulfochloride. The tanning agent dissolved in a little water is added in three portions in the course of six hours. The tanning is complete after two days. The finished pure white leather is very similar to that of Example 1.

Example 3 East Indian sheep skin leather is well fulled in the customary manner and rinsed in running water. Re-tanning follows in 150% of water with 10% of the tanning agent of Example 1 and 1.3% 'of lactic acid. The time of tanning amounts to three hours. The quantities speci- 71 fied are calculated on the striking out weight, aminobenzene '-sulfonyl)-benzidine-m-m'-disul-' SOPNH GNHO One-bath chromium calf leather, thoroughly freed from acid, is fulled for one hour in 150% of water (all the quantities are calculated on the shaving weight) containing 3% of the sodium salt of bis-(l:2-dich1orobenzene-l-sulfonyl-3' P aminobenzene-l -sulfonyl-3. -aminobenzene-l sulfonyl) -benzidine-m-m-disulfonic acid (Brit ish Letters Patent No. 338,559, Example '7) of 1 the formula: a

SOaNa ies I SO Na 1.5% of oxalic acid is then added and fulling continued for three quarters of an hour longer.

After that the leather is rinsed in running water for half an hour and well stufied with 3% of sulfonated neats-foot oil, at 50 C. The chromium leather thus bleached is almost pure white and possesses almost complete fastness'to light.

Example 5 Degreased sheep skins (freefrom lime) treated with a pickle consisting of 0.5% of formic acid, 6% of sodium chloride, and of water'are tanned with a synthetic tanning agent of the 35 probable formula:

.. s oiNm OaNH4 which is obtained by the condensation ofbis -(3- fonic acid (compare British Letters Patent ,No.

333,559, Example 6) with a mixture-of LZ-di-p chlorobenzene-4su1fochloride and 1.4-dich1orobenzene-Z-sulfochioride. Therefore it consists of a mixture of symmetrically and asymmetrically constructed compounds of the above mentioned formula. 2.5% of this product are used, and4'22 parts by weight of a technical 30% acetic acid are added for each 100 parts by weight of the tanningagent. a

After some hours the tanning is performed with the addition of 10% of the tanning agent,

parts by weight of acetic acid and 3 parts by weight of 100% formic acid for each 100 parts by weight of the dry ware.

completely tanned and after a short The acidified concentrated aqueous solution'of the tanning agent isadded in severalportions in the course of one day. Then it is fulled until rinsing it is curried in the customary manner. thus obtained shows the same exclle'n'tproperties as mentioned in Example 1. I

The leather 'In-the examples the tanning agents specified can be replaced ,byother representatives of the compounds denoted by the general formula. Such .products are, for example, the sodium salt of bis- (1 :4-dich10robenzene-2-sulfony1 3 aminobenzene-1'-su1fony1 benzidine -m m disulfonic acid.

SOaNB.

I SOaNa SOaNa I SOzNa or of bis-(naphthalene-1-su1fony1-3-aminobenzene -:1 sulfonyl) -benzidine mm disulfonic acid: I

SOsNa OsNa or of bis- (naphthalene-2-su1fony1-3 -aminobenzene 1 sulfonyl) -'benzidine m.m disu1-f0nic acid:

SOaNa in: 1 o:

I SOaNa I l 1 1m so,

I OH

6) with two molecular proportions of 3-chlorophenoxy-acetylchloride according to-the methods described in the British Letters Patent 313,110, or of bis-(benzoyl-B-aminobenzene-1-su1fony1) benzidine-m-mdisulfonic acid:

1%13 SOaNa ILIH 00 I to obtainable. by condensing one molecular proportion of bis- (3-aminobenzene-sulfonyl) -benzidinem-m'clisulfonic acid (compare British'Letters Patent 333,559, Example 6) with two molecular proportions of benzoylchloride in a known manner, or of bis-(3-acetylaminobenzene-1-sulfonyl- 3-aminobenzene-1-sulfonyl) -benzidine-m mdisulfonic acid:

wherein R stands for a benzene, naphthalene or diphenyl radical, both nuclei of the diphenyl radical beinglinked together directly or by means of a bridge, and R1 and R2 represent dior polynuclear aryl-sulfone arylamide derivatives of the benzene or naphthalene series with chain-like linkage in which the sulfone-imide groups com bining the aryl nuclei may be partly replaced by aliphatic or aromatic carboxylic acid amide groups, and wherein at least one nucleus contains a sulfonic acid group, and wherein all nuclei may be further susbtituted by halogen or all y1- or hydroxyor carboxylicor alkylacetylamino groups.

. s olNa l r nr S OQNa Y 1711 c o o o CHsCO-NH- "NH-coolly obtainable by acetylating the sodium salt of bis- (3-aminobenzene 1 sulfonyl-3'-aminobenzene- 1- sulfonyl) benzidine m mdisulfonic acid (British Letters Patent 333,559, Example 7) in an aqueous solution with an excess of acetic anhydride at a temperature of 49 C. in the presence of chalk and many other compounds of the like constitution. All these products are distinguished by their strong tanning properties as, accordingly,

O-sm-ma- 2. A tanning composition, the active constituent of which is a condensation product of the probable formula:

mastic SOaNa NH 1 V g O2 JOHANN HUISMANN. GUSTAV MAUTI-IE. 

